Title text:
They're up there with coral islands, lightning, and caterpillars turning into butterflies.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3135/
I remember never believing my parents when they explained it to me as a kid. Clouds being caused by cigarette smoke was reasonable but the moon pulling out the ocean seemed too outrageous.